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Tim Demko

@timdemko.xyz
3.3K followers 6.2K following 881 posts

Geologist interested in the energy transition, bicycling, and public service bio.link/timdemko orcid.org/0000-0002-9125-0907 www.semanticscholar.org/author/Timo…

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Reposted by Tim Demko
Callan Bentley @callanbentley.bsky.social · 18h
New video! On the ground in Shenandoah National Park, I check out some structures built by the Civilian Conservation Corps that feature 𝘚𝘬𝘰𝘭𝘪𝘵𝘩𝘰𝘴-bearing blocks of Antietam Formation quartz sandstone (one of which shows spectacular deformation): youtu.be/lKjQ9_B7u9A ⚒️
youtu.be
Skolithos trace fossils in Civilian Conservation Corps structures, Shenandoah National Park
YouTube video by Callan Bentley
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Jake Berv @jakeberv.bsky.social · 30/09/2026
46.4866001, -87.6546617
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Vicky Veritas @vickyveritas.bsky.social · 17h
Boudinage are one of the most spectacular geologic structures and some of my favorite rocks. The boudins are the eye-shaped lenses of rock wedged between the white quartz layers. This happened when the rocks were being stretched by tectonic forces. The eye-shaped lenses, augen… 👇🏼 #MinCup26
Boudins of amphibolite layers (metamorphosed basalts) that were stretched between quartz schists (Norway). Photo credits: Haakon Fossen.
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Paul D. Taylor @nhmbryozoa.bsky.social · 14h
Published today and fully Open Access: doi.org/10.1017/jpa....
doi.org
The fossil record of bioerosion | Journal of Paleontology | Cambridge Core
The fossil record of bioerosion
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Matt Friedman @friedmanlab.bsky.social · 10h
Teaching on the main campus so no collections work today. So here's Bothriolepis canadensis (UMMP VP 3475) from this week's lab for the vertebrate paleontology course.
Bony armor of a placoderm fish with tiny eyes. The fossil is dark in color and shaped like an egg.
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John Van Hoesen, Ph.D. @jvh-vt.bsky.social · 10h
Fantastic detail in this 1920 OS map: inclines, railways & mill buildings surrounding Blaenau #Ffestiniog, #Wales. #geology #thestoryofslate
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Ben Miller @extinctmonsters.bsky.social · 29/09/2026
Well this is bleak. And why did they wait a week after the news leaked just to say "we have no plan?"
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Brandon Bishop @brandontbishop.bsky.social · 29/09/2026
This is going to be *so* destructive to North American paleontology, for both the Cretaceous Interior Seaway and Neogene mammals. All because of state-level ideologies that hold tax cuts and slashing spending are the only thing that can ever be done.
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Andrej Spiridonov @andrejpaleo.bsky.social · 26/09/2026
Updated Fossilworks 🧪⚒️ #Geology #Paleobio #EvoBio
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Alexis Rastier 🌿 @alexisrastier.bsky.social · 26/09/2026
What an extraordinary journey to Münster (Germany) for the European Paleobotanical and Palynological Conference (EPPC) 🌿 I was honored to present my research at the Early Career Symposium on a new whole-plant reconstruction of a rhacophytalean fern from Bjørnøya.🇳🇴⚒️ #Paleobotany #Devonian #Fern #EPPC
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British Geological Survey @bgs.ac.uk · 26/09/2026
The BGS maps portal provides access to over 45,000 high-res viewing images of almost all maps produced by BGS since mapping started in 1832. This sheet is from 1852. It shows North part of Anglesey, and part of Holyhead Island Mineral Lodes. Access the portal: www.bgs.ac.uk/information-...
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Andy Farke @andyfarke.bsky.social · 24/09/2026
Fossils as cultural heritage: Scientific, commercial and legislative issues - Fanti - 2026 - Geology Today - Wiley Online Library onlinelibrary.wiley.com/doi/full/10....
onlinelibrary.wiley.com
Fossils as cultural heritage: Scientific, commercial and legislative issues
Fossils are among the principal sources for understanding the history of life through ‘Deep Time’ and can inform projections of biotic responses to environmental change. Despite a widespread recognit...
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Callan Bentley @callanbentley.bsky.social · 24/09/2026
Shrimp! Cenomanian (earliest Late Cretaceous), of Lebanon. ⚒️
Darker brown shrimp fossil.in tan limestone, with a white fracture running through it.
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Patrick Wyman @patrickwyman.bsky.social · 24/09/2026
Outstanding new review of ALL of the currently available DNA evidence for the peopling of the Americas, led by Bethany Potter (and the amazing @jenniferraff.bsky.social!): www.sciencedirect.com/science/arti...
sciencedirect.com
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Dr. Wendy Bohon @drwendyrocks.bsky.social · 24/09/2026
Cool girls have cool jobs 😎
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Robbi Bishop-Taylor 🛰️🌏 @satellitesci.bsky.social · 24/09/2026
It's been a long time in the making, but our new #opensource paper has just been published in Remote Sensing of Environment! 🛰️🎉 "Time and tide: Mapping the changing 3D shape of Australia's dynamic intertidal zone using time series satellite data" www.sciencedirect.com/science/arti...
Scientific figure showing DEA Intertidal outputs
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Harold Tobin @haroldtobin.bsky.social · 24/09/2026
Back from a 5 day backpacking-as-field-work venture into the Olympic mountains interior. We covered 45 miles on the Skyline Ridge trail and back, with 16,000 feet of total vertical in 5 days. All to recon another swath of deeply subducted rocks from the paleo-seismogenic zone. Subduction rocks! ⚒️
Two geologists hiking along steep bare hillside seen from behind, with distant moountain ridge and blue sky.  Close up shot of rock outcrop of severely deformed meta-sedimentary rocks with a block-in-matrix melange fabric. Pencil shown for scale. Geologist standing at dusk against a rocky landscape, brushing their teeth with a headlamp on. Person stands on rocky knob against blue skyline with Mt. Olympus (Washington) in background.
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Dave Petley @davepetley.bsky.social · 24/09/2026
A new paper (He et al. 2026) in the journal Landslides describes the breach of the massive Matai'an Rover landslide dam in Taiwan in September 2025, which killed 24 people. eos.org/thelandslide...
The aftermath of the Matai'an landslide dam breach. Image using images from Planet Labs, from He et al. (2025).
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Aaron Kufner @akufner.bsky.social · 23/09/2026
This one has been a long time coming! I'm happy to share that another chapter of my PhD has been published! In this one, I'm shaking up the taxonomy of North American metoposaurids. This work was largely done in museum collections, and more on that below. peerj.com/articles/217...
A figure with maps showing the distribution of metoposaurid occurrences in Upper Triassic outcrops of western and eastern North America (centered on the USA). The approximate chronostratigraphic ranges of the now five recognized species are plotted, and line drawings of all of the potentially or definitively diagnostic holotypes of North American metoposaurids are included.
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Joe Mason @moreorloess.bsky.social · 24/09/2026
Beach ridge complex and dunes at Pointe aux Chenes, Michigan. I've got it in my slides for a case study on post-glacial rebound and other causes of lake level change on the Great Lakes, and I had to post it here again.
A shaded relief map of a very impressive set of concentric beach rdiges, and on the west side a coastal dune field, along the shore of northern Lake Michigan.
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Andy Rivkin @asrivkin.bsky.social · 22/09/2026
The answer is “samples from sites specifically chosen as having young lunar basalts (as estimated from crater counts) to serve as benchmarks to make the lunar dating system, and thus inner solar system age estimates, more accurate and robust”. (cc @barbylon.bsky.social)
iopscience.iop.org
In Situ Geochronology for the Next Decade: Mission Designs for the Moon, Mars, and Vesta
In Situ Geochronology for the Next Decade: Mission Designs for the Moon, Mars, and Vesta, Cohen, Barbara A., Young, Kelsey E., Zellner, Nicolle E. B., Zacny, Kris, Yingst, R. Aileen, Watkins, Ryan N., Warwick, Richard, Valencia, Sarah N., Swindle, Timothy D., Robbins, Stuart J., Petro, Noah E., Nicoletti, Anthony, Moriarty, Dan P., Lynch, Richard, Indyk, Stephen J., Gross, Juliane, Grier, Jennifer A., Grant, John A., Ginyard, Amani, Fassett, Caleb I., Farley, Kenneth A., Farcy, Benjamin J., Ehlmann, Bethany L., Dyar, M. Darby, Daelemans, Gerard, Curran, Natalie M., van der Bogert, Carolyn H., Arevalo, Ricardo D., Scott Anderson, F.
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Celeste Labedz @celestelabedz.bsky.social · 22/09/2026
It's been so sad watching my alma mater in the last decade, especially as the Earth and atmospheric science department was eliminated. Nebraskans (and the world!) deserve long-term investment that builds great education and research in Nebraska.
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AAUP @aaup.org · 22/09/2026
"The elimination of entire departments to achieve relatively modest short-term savings risks long-term damage to research capacity, student enrollment, and institutional reputation." – Todd Wolfson, AAUP President
journalstar.com
Faculty group urges AAU to deny UNL readmission over budget cuts
The American Association of University Professors called the University of Nebraska-Lincoln's push to gain readmission to the AAU into question following last year's program and position eliminations.
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Matt Friedman @friedmanlab.bsky.social · 22/09/2026
Wow! Great news for the BGSU paleobiology program. Congrats to @pegyaco.bsky.social and colleagues: www.bgsu.edu/news/2026/09...
bgsu.edu
More than $1 million in gifts expands opportunities for BGSU paleobiology students
More than $1 million in gifts from BGSU alumna Sue Goldstein, Ph.D., ’74 and the estate of longtime professor Don C. Steinker, Ph.D., will expand research, fieldwork and professional opportunities for...
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Seismological Society of America @seismosocam.bsky.social · 21/09/2026
🌟 OPEN ACCESS 🌟 A DAS network in northeastern Italy spans several hundred kilometers of optical fiber, and includes tens of thousands of virtual sensing channels. It’s been integrated into the operational framework of the Seismological Research Center of OGS. #SRL ⚒️ buff.ly/nz2Q7dz
Spatial distribution of manholes along the first segment of the Palmanova fiber‐optic route. Manholes provide access points for inspection and maintenance and host spare fiber coils used to accommodate installation and repair requirements.
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Seismological Society of America @seismosocam.bsky.social · 20/09/2026
🌟 OPEN ACCESS 🌟 Scientists use seismic noise to explore the structure and geometry of southern Spain’s Guadalquivir River sedimentary basin. #SRL ⚒️ buff.ly/LCIVkyD
Interpretation of the mHVSR analysis results.
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Brandon Bishop @brandontbishop.bsky.social · 21/09/2026
Bilal Haq is, personally, the reason we understand sea level change over geologic time.
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Andrej Spiridonov @andrejpaleo.bsky.social · 21/09/2026
The macroscale occurences of iron-rich duricrust regoliths in South-Eastern Africa reflects Eon-scale evolution of the megaclimate in this region. With warm and humid periods corresponding to Devonian, Late Cretaceous and Quaternary. www.nature.com/articles/s43... 🧪⚒️ #Geology
The up-to-date model of evolution of theNPthrough the geological times.Localization, geological characteristics and uplift history of the Nyika
plateau (NP)
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Lithosphere Journal @lithospherejournal.bsky.social · 21/09/2026
Call for Papers: Precambrian Crustal Processes A new Special Issue is now open for submissions, focusing on the processes that shaped Earth’s earliest crust across the Hadean, Archean, and Proterozoic eons. Learn more at: pubs.geoscienceworld.org/lithosphere/...
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Jonathan Parkes Allen @jparkesallen.bsky.social · 21/09/2026
There is a foraminifera sculpture park in Zhongshan, Guangdong, the outcome of the vision of Pakistani-American marine geologist Bilal Haq and Chinese marine biologist Zheng Shouyi, honestly there should be more in more cities
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Seismological Society of America @seismosocam.bsky.social · 21/09/2026
In a new #SRL paper, scientists compare earthquake wavefield measurements from an approximately 95 km-long urban dark fiber distributed acoustic sensing array in Dallas, Texas with data from a co-located broadband seismic array. ⚒️ buff.ly/HufKBLN
Section of the Range Hill earthquake record after the removal of the aerial and slack cable DAS channels for the complete 95 kilometers or so fiber cable loop at 10.2 meter channel spacing.
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Matthew Morriss @rockiceandsnow.bsky.social · 21/09/2026
At the Utah Geo Survey, we've been debating which 7.5' quadrangles have the most surface area. We have our answer and it was surprising! This proxy for normalized relief put the western Tavaputz Plateau as the highest compared with other regions #madewithClaudeCode
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Brandon Bishop @brandontbishop.bsky.social · 21/09/2026
The goal, of course, is to get a big enough part of the educated public *waves at Bluesky* demanding research into things like the pre-Last Glacial Maximum Pleistocene or the tectonics that shuttered (or opened) circum-planetary ocean circulation or The Great South American Biological Experiment, or
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Ian Saginor @volcanoclast.bsky.social · 20/09/2026
A moody quartz sandstone thin section. Like a cold December morning. #MinCup26 #Quartz
Thin section of quartz sandstone.
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Ben Collins @bencollins.bsky.social · 19/09/2026
Angine de Poitrine fucking rules.
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Alberta Claw @albertonykus.bsky.social · 18/09/2026
Reevaluation of the taxonomy of Solnhofen avialans, this time supporting the distinction of Alcmonavis from Archaeopteryx: fr.pensoft.net/article/2002... 🪶🧪 (📷Foth & Rauhut)
Line drawings comparing the wing bones of several fossil bird-like dinosaurs, along with close-up photographs of two particular specimens.
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Andrej Spiridonov @andrejpaleo.bsky.social · 16/09/2026
"We find three macroevolutionary transitions in mammal assemblages... regional Asianmid-Eocene aridification and...global events—the Paleocene-Eocene Thermal Maximum (...warming 56Ma) and the Eocene-Oligocene Transition (prolonged cooling 34Ma)." www.nature.com/articles/s41... 🧪⚒️ #Geology #Paleobio
Sampling-corrected estimates for richness, turnover, and body mass for total Mammalia, spanning the Paleocene, Eocene, and Oligocene Epochs and corresponding Asian Land Mammal Ages (ALMAs).
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Peter Brannen @peterbrannen.bsky.social · 16/09/2026
RIP to Annie Dillard, whose work frequently left me unable to speak sensibly for several minutes after reading it. This essay, This Is The Life, was my entry point for her work
Annie Dillard's This Is The LifeAnnie Dillard's This Is The Life
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Cam Muskelly (Explorer of Deep Time ⏰ ⚒️) @cambriancam.bsky.social · 16/09/2026
It's 96 degree weather here in Mississippi collecting fossils from the Late Cretaceous (Late Campanian) Demopolis Formation. ~76 million years ago, the black belt region of Mississippi and Alabama was covered in a warm shallow sea teeming with life. The round objects you see around me are oysters!
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The Palaeontological Association @thepalass.bsky.social · 16/09/2026
Tetrapod cololite from a middle Permian lagoon community in European Russia & its implications for palaeoecological reconstruction onlinelibrary.wiley.com/doi/10.1002/... #PapersinPalaeontology
Upper left: photograph of a yellow-brown rock sample containing a fragment of the postcranial skeleton of a reptiliomorph (?Nyctiboetus kassini) (darker brown) with cololite from the Shikhovo–Chirki locality (PIN 161/180). Scale underneath is 10 mm.
Lower left: interpretative sketch of the specimen showing tetrapod remains in brown, fields of scales (paler brown), the cololite in grey and undigested remains in red.
Upper right: tentative reconstruction of the fragmentary skeleton in dorsal view; the bones in red are preserved and the cololite is shown in blue.
Lower right: reconstruction of the postcranial skeleton with cololite, based on CT data. Scale bar in lower right corner is 5 mm.
Red rectangle on right side is a cover image from the journal Papers in Palaeontology.
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Hady George @houdzgeorge.bsky.social · 16/09/2026
Welcome Dinodontosaurus isiyavamanda! I'm delighted to introduce you to a new species of protomammal. Hailing from the Triassic of Tanzania, this is the first record of Dinodontosaurus outside of South America, and it informs on the origin of dinosaurs. Here's a thread summarising our findings 🧵
Life reconstruction of two Dinodontosaurus isiyavamanda individuals by Gabriel UguetoSkull and jaw of the holotype of Dinodontosaurus isiyavamanda. Original photos by Jonathan Jackson
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Mineralogical Society of America @mineralsocamerica.bsky.social · 16/09/2026
American Mineralogist: Evaluation of the Mg-in-magnetite geothermometer and development of new magnetite geothermometers using machine learning Xing-Hao Gao, Hao Hu, Guo-Xiong Chen, David Lentz, Heng Luo, Xiao-Ming Li, Zhe Ren doi.org/10.2138/am-2...
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Seismological Society of America @seismosocam.bsky.social · 16/09/2026
DAS Dataset and Processing Results for Microseismic Events Recorded During the 2024 Stimulations at the Utah FORGE Site #SRL ⚒️ A new DAS dataset can advance our understanding of enhanced geothermal systems. buff.ly/PTKmRaI
Rate of temperature change derived from distributed temperature sensing data showing the progressive damage experienced by the fiber optic cable in well 16B.
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John Van Hoesen, Ph.D. @jvh-vt.bsky.social · 16/09/2026
Detailed image of Penrhyn Quarry, North #Wales c1880s showing use of rails along benches and a few blast shelters. Very different from today's view! #geology #thestoryofslate
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Alessandro Chiarenza @macroecoevoale.bsky.social · 16/09/2026
How do you take the temperature of a T. rex 66 million years too late? Time machine? Impossible. Billionaire’s dinosaur island? Risky. Geochemistry? Much safer 🦖🌡️ Our new Science Advances paper adds evidence for an endothermic, “warm-blooded” T. rex, link to the paper 🔗 doi.org/10.1126/scia...
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Jon Phillips @jowiph.bsky.social · 16/09/2026
Imo, it's worse than that. A large segment of our current elites (somewhat overlapping with the ones you describe) have become a cohort of Raputins themselves.
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Davor Mondom @dmondom.bsky.social · 16/09/2026
A large segment of our latter-day elites are Nicholas II enraptured by their version of Grigori Rasputin (be that X, AI, their cadre of yes-men, what have you)
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Olúfẹ́mi O. Táíwò @olufemiotaiwo.bsky.social · 16/09/2026
if you doubt a ruling class could possibly be this world historically wrong I'll note that "We have nothing to fear on the part of the Negroes; they are tranquil and obedient” and “We sleep with doors and windows wide open. Freedom for Negroes is a chimera” are quotes of a slaveowner in 1790, Haiti
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Earth Archives @eartharchives.org · 16/09/2026
A swollen patch on an Iguanodon shinbone may be the first evidence of an infected skin ulcer reaching the bone in a dinosaur. Image credit: Royal Society Open Science (2026). DOI: 10.1098/rsos.261293. phys.org/news/2026-09... #fossils #paleontology
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Dr. Jennifer Wade @volcanojw.bsky.social · 14/09/2026
Do you like maps?? I’m in a briefing where the USGS shared these amazing 3D Elevation images that are just so cool. Find your state/district, and behold this example of DC! www.usgs.gov/3d-elevation...
A 3D Elevation Program image from the USGS of the District of Columbia, depicting (in their words) “the ‘bare earth’ surface, stripping away vegetation and structures, revealing ground surface.
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